Low-water-signal apparatus for steam-boilers



L. NICHOLAS. LOW WATER SIGNAL APPARATUS FOR STEAM BOILERS;

APPLICATION FILED DEC. 5.1919. 1,376,966. Patented y 3, 1921.

WSW... I 9 a 1 s [I V INVENTOR: W ATTORNEY.

44 A. .6 F W 0 mi /1 57"? fl 2 U WI 'I'NESS:

siren LEwIs NICHOLAS, or INDIANAEOLIS, INDIANA.

LOW-WATER-SIGNAL APPARATUS non STEAM-BOILERS.

T 0 all whom it may concern:

Be it known that I, LEWIS NICHOLAS, a citizen of the United States, residing at Indianapolis, in the county of Marion and State of Indiana, have invented a new and useful Low-Water-Signal Apparatus for Steam- Boilers, of which the following is a specification, reference being had to. the accompanying drawings, and to the letters and figures of reference marked thereon.

a This invention relates to a locomotive type of steam-boiler or one provided with a metallic fire-box having. a crown. sheet exposed ,tointense heat and covered in operation by An object of the invention is to provide an automatic p safety signal designed to indi-:

cate to e the engineer or attendant when a dangerously low level of water in the steamboiler occurs, which may result when the steam-boiler is not fed or is insufficiently fed with. water. u

signal apparatus for steam-boilers which Another-object is to provide simple, posi tive and reliable'means for sounding a low water alarm when, because; of operating noises, escaping steam might not be heard,

when afusible plug in the crown sheet be comes melted, or. in case a visible signal might not be observed.

A further object is to provide a low water shall be so constructed as to include means for stopping the escape of water or steam 1 into the'fire-box after a fusibleplug has melted,.in order to preventserious loss of v water andpermit further operation of the steam-boiler or continuance vof a trip of the locomotive to destination when a new fusible plug may be supplied.

provided with means for closing the aper ture left when the-plug is melted, the apparatus being adapted toautomatically oper-,

ate an alarm devicepromptly when the fus- Specification of Letters Batent.

ible plug is destroyed; and, the invention consists also further in the parts and combinations'and arrangementsof parts as hereinafter particularly described and further defined in the accompanying claims;

Referring to the drawings,Figure 1 is a fragmentary vertical section of a locomotlve type steam-boiler and'fi're-box to which the inventionis applied; Fig. 2 is a frag mentary sectional view of the steam-boiler V and a central sectional elevation of the safety appliance on an enlarged scale; Fig. 3 is a view slmllar to thatin the preceding figure but showing the signal operating device in' a different position permitting operation of the steam-boiler after the fusible element has been melted away; Fig. 4 is a top plan of one of the devices of the invention which assists in holding the fusible element in position and affords means'to permit operation of the'boiler after disappearance of the fusible element; and, Fig. 5 is a side view of the fusible element as preferably constructed. 7

Similar reference characters in the different figures of the drawings indicate corresponding elements or features of construction herein referred to in detail,

I In the drawings the numeral 1' indicates the barrel, 2 the flue sheet, 3 the fire-box crown sheet, 4 the shell or outer sheet of the fire-box, 5 the boiler head, and 6 the rear end of the fire box of a familiar type of locomotive steam-boiler, in connection with which .is a cab having a front 7 extending over the shell 4 of the fire-box. I

The improved safety appliance comprises a plug 8 which is screw-threaded and inserted in a suitable opening in'the crown sheet 3 and it has a relatively small neck 9 on its upper portion which is screw-threaded externally, the neck having a flat top 10;

Patented May 3, 1921. Application filed December 5, 1919. Serial no. 242,715.

and, the plug has a bore ll'extending therethrough to receive fire-box heat. he upper portion of the bore is closed by a suitably shaped piece of metal that is fusible at a deplaced upon the top 10 of the plug and hav-- ing a boss 13 on its top. A cylinder l l is vprovided which has a cylindrical bore 15 extending from its top downward to an annu- The fusible element lar ledge 16 formed in the cylinder to con- V stitute an annular valve seat which has an opening 17 adapted to closely receive the.

1 less in diameter than the bore of the cylinder to permit water or steam to leak past the piston valve, the under side of the latter hav ing a valve face 22 adapted to engage the valve seat and close the o ening 17 when the fusible piece is absent. referably the valve stem 20 has a stop collai'28 fixed thereon to limit the upward movement of the valve stem when brought into contact with the under side of the packing box. The outer end of the valve stem 20 has a head 24 thereon which preferably is removable from the stem. At a suitable distance from the packing box a standard 25 is secured to the shell 4 and pivotally supports a bell-crank'having an arm 26 that is detachably connected with the head 24 and being horizontally extended, the bell-crank having another arm 27 extending upwardly. A steam-whistle 28 is connected to the shell 4 so vas to utilize steam from the steam-boiler and it has a suitable operating lever 29 to which a rod 30 is connected which is connected also with the bellcrank arm 27. The signal whistle shown is of familiar type but may be variously con structed; and, as will be understood, the steam-boiler and fire-box may be variously constructed as to details.

In practical use the crown sheet of the fire-box is covered with water sufliciently to prevent over-heating of the crown sheet, and the piston valve is held at a distance from the fusible element and permits the fusible element to be covered with water. In case the water becomes so low as to not. afforddownward so that the bell-crankconnected with the stem shall be operated and through the remaining connections cause operation of the signal whistle, wh1ch will notify the water which can not be obliterated under the usual conditions of operation. While the crown sheet is still sufiiciently covered with water to safely permit feeding the boiler, the head 24may be disconnected from the bellcrank arm 26, after which the valve stem 20 may be pushed downward or permitted to descend until the pistonvalve becomes seated so as to close the opening 17 the piston valve being then held in place by the steam pressure, after which the boiler may be fed with waterto permit continua ance of the trip to destination without further inconvenience, assuming that the steam" boiler will be properly supplied with Water,

Frequent inspection of fusible plugs in steam-boilers being required, the improved safety devices may be readily examined after withdrawing the plug 8 and the cylinder 14 through the crown sheet and away from the piston valve, and releasing the-fusible element if desired to further inspect it, and

then a new element may be quicklyinserted in place if required.

Having thus described the invention, what is claimed as new is l. A low-water signal apparatus including a hollow plug, a fusible element'rem'ow ably seated upon the top of the plug,a hollow cylinder screwed onto the plug and having a valve seatledge therein engaging the fusible elementand securing it to the plug, the cylinder having an open' unobstructed upper portion, a piston valvefreely' received into the upper portion of the cylinder and movable to the valve seat ledge on removal of the fusible element, and an operatingstem connected to the piston valve.

2. In low-water signal apparatus, the

combination with a plug having a neck and a clear bore extending through theneck and the remainder of the plug, the neck and the remaining portion of the plug each having screw threads on the outer side thereof, and a fusible element on the top of the plug, of a hollow cylinder having avalve seat ledge on the inner side thereof and also screw threads extending from one end there of toward the ledge to engage the screw threads on said neck and hold said ledge on said plug, the cylinder having a bore ex tending from the opposite end thereof to the ledge, a piston valve receivable into the top of the bore in the cylinder, and an op crating-stem connected to the piston" valve.

3. In low-water signal apparatus, the combination with a hollow plug and a fusible element on the top of the plug, of a hollow cylinder secured to the plug andhaving a valve seat ledge therein engaging the fusible element and securingit to the plug, the cylinder having a bore extendingfrom its top to the ledge, a piston valve freely receivable into the'bore in the cylinder, a stem connected to the valve and havinga head secured to its end and having also a stop collar thereon between said valve and said head, a standard, and a bell-crank pivoted to the standard and having an arm pivoted to said head, the bell-crank having also a signal-operating arm thereon. i

4. In a low-water signal apparatus, the combination with an operative signaling device, a hollow plug, and a fusible element on the top of the hollow plug, of a hollow cylinder secured to the hollow plug and having an annular valve seat ledge integrally fixed] the absence of the fusible element, said valve having a stem,'a pivotally supported bell-i. crank pivotally connected with the valve stem, and a rod connected with. the bellcrank and signaling device.

In testimony whereof, I afiix mysigna ture in presence of two witnesses.

LEWIS NICHOLASL Witnesses: I 7

E; T. SILvws, i F. M. ROEDER. 

